Small-amplitude synchrotron tune near transition

Ng, K.Y.

Fermi National Accelerator Laboratory

关键词: Protons;    Synchrotron Radiation;    Storage Rings;    43 Particle Accelerators;    Electrons;   

DOI  :  10.2172/982478
RP-ID  :  FERMILAB-FN-0852-AD
RP-ID  :  AC02-07CH11359
RP-ID  :  982478

美国|英语

来源: UNT Digital Library

【 摘 要 】

The separatrices of the rf buckets near transition are mapped when the synchronous phase is neither 0 or {pi}. The small-amplitude synchronous tune is derived when the rf frequency is changed. Synchrotron radiation is present in all electron storage ring. As a result, the synchronous phase is always offset from {phi}{sub s} = {pi} to compensate for the power loss. Even for proton storage rings with negligible synchrotron radiation, the synchronous phase is also required to be offset from {phi}{sub s} = 0 or {pi} slightly to compensate for beam loading. Thus for all storage rings operating near transition, beam particles reside in accelerating buckets instead of stationary bucket. It is of interest to map these buckets and see how they evolve near transition. When the rf frequency is varied, the closed orbit is pushed radially inward or outward. The momentum of the particle synchronous with the rf is thus changed. By measuring the small-amplitude synchrotron tune as a function of the rf frequency, the lowest first few orders of the slip factor can be inferred. Here, we derive this relationship up to the lowest first three orders of the slip factor when the particle velocity is not ultra-relativistic.